Field of the Invention
The present invention relates to a device for controlling the amount of light emission of an electronic flash apparatus.
As a conventional light emission controlling device of this type, a TTL automatic light-adjusting device is known in which the light reflected from the object is received by one light-receiving element and, when the amount of light received, i.e., a photometric value, reaches a predetermined value in correspondence with a reference exposure, the emission of light is stopped. In addition, as disclosed in Japanese Pat. Laid-Open No. 62-90633, a device is known in which multiple-division metering is carried out, and control of the amount of emission is conducted on the basis of the largest value thereof. In addition, as disclosed in U.S. Pat. No. 4,589,756, a method of multiple-division metering is known as a method of controlling the exposure of photographing under normal light.
However, with a conventional TTL device, there is a problem in that, in cases where the light reflected from the subsidiary object is extremely stronger or weaker than the light reflected from the main object, if emission is stopped at a predetermined value corresponding to a reference exposure, an appropriate exposure cannot be obtained for the main object. In addition, with the above-described conventional light emission controlling device of the multiple-division metering method, since the maximum value among the divided measurement values is used as the criterion for stopping the emission, in cases where, for instance, the subsidiary object is located at a position closer to the light-emitting tube than the main object, there are cases where it is impossible to obtain an appropriate exposure in the same way as described above. Furthermore, the conventional multiple-division metering method used in photographing under normal light takes time in performing a calculation since a complicated calculation of exposure is required, so that it has not been able to control an apparatus in which light emission is completed within a very short time, such as an electronic flash apparatus.